Multiple clutch strip tensioner

ABSTRACT

A tensioner for tensioning individually a number of strips that are being rewound side by side simultaneously. The tensioner includes two shafts rotatably carrying opposed rollers, one pair for each strip. The rollers are separated by friction discs keyed to the shafts, the rollers and friction discs being compressed axially together so a pair of rollers rotates on its shafts only when a predetermined tension is exceeded at the strip passing between them. Sideways movement of strips is prevented by separater discs between the rollers. The shafts are rotated at a speed less than the rewind speed of the strips, to reduce slippage between the rollers and the friction discs.

United States Patent [1 3 Tilban Dec. 17, 1974 MULTIPLE CLUTCH STRIP TENSIONER Primary ExaminerJ0hn W. Huckert [76] inventor: Ferenc Tilban, 310 Niska Rd., Apt. Asssmm Mecerthy,

l 103, Downsview Ontario Canada Attorney, Agent, or FtrmRogers, Beresk1n & Parr [22] Filed: Feb. 21, 1973 57 ABSTRACT PP N05 334,302 A tensioner for tensioning individually a number of strips that are being rewound side by side simulta- 521 US. Cl. 242/75 2 226/195 neeusly- The teneiene' eludes shefs etatebly 51 Int. issh 23/14 earrying eppeeed rollers One Pair fer eeeh The [58] Field of Search 242/752 56 2- 226/39 reliefs are separated by friefie dises keyed 226/l95 shafts, the rollers and friction discs being compressed axially together so a pair of rollers rotates on its shafts [56] References Cited only when a predetermined tension is exceeded at the strip passing between them. Sideways movement of UNITED STATES PATENTS strips is prevented by separater discs between the rol- FOLIlOIH X 1 -5 The hafts are rotated at a peed less than the re- 2 g g? wind speed of the strips, to reduce slippage between 8x972 2; m 2 the rollers and the friction discs.

4 Claims, 6 Drawing Figures PATENTEBUEEI H914 3.854.672 SHEET 1 0F 5 CURRENT CLUTCH ELECTRIC MOTOR MULTIPLE CLUTCH STRIP TENSIONER 4 stock may be broken. The tension in the coils tends to vary considerably from coil to coil because of variations in the thickness of the stock and thus in the diameter of the unwound coils, so difficulties have been experienced in maintaining proper tension in each of the coils.

Present practice when rewinding slit stock is to have FIG. 6 is a side view, partly in section, of a portion of a shaft of' the FIGS. 1 to 5 tensioner with modified means for adjusting tension.

Reference is first made to FIG. 1, which shows a conventional uncoiler stand 2 which rotatably supports a roll 4 of stock 6 of material (such as thin steel, plastic, paper, etc.) required to be slit. The stock 6 is withdrawn from the uncoiler stand 2 by drive rollers 8 and then passes between slitters 10 which slit the. stock into a plurality of thin strips. From the slitter 10, the stock is drawn through a tensioner 12 according to the invena workman observe the tightness of the coils to be re wound, and if one coil appears too loose, the workman inserts strips of paper into that coil so that the paper is wound with the stock. This increases the tension and ensures that the resulting coil will not collapse. However, this method is costly in terms of labour, dangerous to the workman inserting the strips of paper, and in addition, when the stock is being used, any strips of paper that are not removed can cause damage to the processing machinery (which may be a roll former if the stock is steel, a printing press if the stock is paper, etc.).

Accordingly, the invention provides in a preferred embodiment, a tensioning device for tensioning the slit strips before they are rewound. The tensioning device in its preferred form includes a pair of shafts, each having plurality of roller rings, the roller rings of one shaft being opposed to those .of the other shaft, with each strip being guided between an appropriate pair of roller rings so that the roller rings, which are coated with a friction material, bear on the strips. Rotation of at least one of the shafts and of the roller rings on it is controlled so that the roller rings on such shaft tend not to rotate as the strip stock passes between the roller rings, thus tensioning the strip stock. When a predetermined tension is exceeded in any strip, the controlled roller ring for that strip is allowed to rotate sufficiently to maintain the tension at the predetermined tension. Thus, the tension of each strip is controlled separately automatically.

Further objects and advantages of the inventionwill appear from the following description, taken together with the accompanying drawings, in which:

FIG. 1 is a diagrammatic view showing an uncoiler, slitter, a tensioneraccording to the present invention, and rewind apparatus;

FIG. 2 is a side view, partly in section, of a tensioner according to the invention;

FIG. 3 is an end view of the tensioner of- FIG. 2;

FIG. 4 is a view, partly in section, of a shaft of the FIGS. 2 and 3 tensioner showing various components in place on the shaft;

FIG. 5 is a diagrammatic side view showing the shafts of the FIGS. 2 and 3 tensioner connected through a clutch to a motor; and

ing, the rolls of the tensioner 12 should rotate slightly I more slowly than those of the rewind unit 14, so as to exert drag on the slit stock as it is rewound. In accordance with the invention, a suitable tensioner 12 for this purpose is shown in FIGS. 2 and 3.

The tensioner 12 includes a base 16, a pair of upright members 18, 20, and lower and upper parallel spaced Each shaft 22, 24 includes a number of roller rings I 34. One roller of each shaft is provided for each strip to be slit and is .of the same width as such strip. Each roller ring 34 is typically formed from two spaced parallel'annular steel plates 36 joined by a cylindrical steel plate 38 having its edges welded to the plates 36. The axis of cylindrical plate 38 coincides with that of the shaft on which it ismounted. Plates 36 are journalled on the shafts 22, 24 by bearings 40 (which may be bronze bushings, ball bearings,etc.) so that "each roller ring 34 is free to rotate on its associated shaft 22 or 24. The outer face of each cylindrical plate 38 is covered with a friction facing 42, for a purpose to be described. Facings 42 may be of material such as the rubber sold under the trade mark Neoprene, and are typically bonded to plates 38.

The roller rings 34 are separated and spaced apart by annular friction discs 44. Each friction disc 44 includes a pair of keys 46 (FIG. 4) which project into keyways 48 cut into the shafts 22, 24, so that the friction discs 44 can slide along the shafts but are not rotatable thereon. The outer diameter of each friction disc 44 is.

less than that of the roller rings 34, leaving an air gap .50 of height H and width W between adjacent roller rings. The side faces of the annular plates 36 of the roller rings are relieved as shown at 52, so that the spacing W is less than the full width of the friction discs 44.

As shown in FIG. 2, the gaps 50 between the roller rings 34 of the upper shaft 24 accommodate annular separator discs 54. The separator discs 54 are each of width less than width W and of inner diameter very slightly greater than the outer diameter of friction discs 44, so the separator discs rotate freely on the friction discs 44 and can slide sideways on them. (The width of separator discs 54 is of course considerably less than the width W of air gaps 50.) The outer diameter of the separator discs 54 is substantially greater than the outer diameter of theroller rings 34 (by an amount typically greater than one-half H but less than H), so that the separator discs 54 project substantially into the gaps 50 between the roller rings 34 of shaft 22. As may be seen from FIG. 2, the separator rings 54 serve to prevent strips of the stock 6 located between a given pair of roller rings from sliding sideways onto another pair of roller rings.

The assembly of friction discs 44 and roller rings 34 on each shaft 22, 24 is maintained under controlled axial compression by a pair of annular end discs 56, 58

located on each shaft at opposite ends of the friction disc-roller ring assembly. End disc 56 (which is keyed to its shaft) abuts against the left hand friction disc 44 and is held against axial movement to the left as shown in FIG. 2 by a stop ring 60 fixed to the shaft and having a spring disc 62 which presses against the end disc. The right hand end disc 58 (which abuts against the right hand friction disc, not shown) is keyed to the shaft and is held against axial movement to the right by another stop ring 64 and spring disc 66 which are spaced by a washer 68 from a nut 70 threaded on the shaft. Thus, the compression of the friction disc-roller ring assembly-on each shaft 22, 24 can be controlled by turning nut 70 to move this nut either to the left (which will increase the compression) or to the right (which will reduce the compression).

As indicated in FIG. 2, the shafts 22, 24 have projecting ends 72, 74 respectively. As shown diagrammaticallyin FIG. 5, the shaft ends 72, 74 are connected by universal joints 76 and by flexible couplings 78 to the gears 82 of an adjustable rotation controlling device 83 such as an eddy current clutch, or the like, which in turn is connected to an electric motor drive 84.

In order that slit stock 6 of different thicknesses may be accommodated between the roller rings 34 of the upper and lower shafts, the height of the upper shaft 24 can be adjusted by a hand wheel 85, which turns a shaft 86. The shaft 86 operates gear mechanisms shown in block form at 88 to raise and lower shafts 90 which carry the bearing housings 92 for upper shaft 24.

The operation of the tensioner is typically as follows. Firstly, the tension at the clutch 83 is set slightly higher than the desired tension level. For example, if the desired tension level at which the slit stock 6 is to be rewound is 80 lbs., the clutch 83 is set to maintain a tension of about 90 lbs. Next, the tension level of the friction plate-roller ring assemblyis set at the desired level, e.g., 80 lbs., so that any spacer ring will rotate when the pull on it exceeds 80 lbs. This is accomplished by turning the nuts 70 to compress the friction plate-roller ring assemblies to the required extent. (Normally each nut 70 will be calibrated with a scale thereon and a cooperating mark on the shaft 22 or 24.) The upper shaft is then raised by turning hand wheel 85, the slit stock is fed in and fed onto the rewind unit 14, and the upper shaft 24 is then lowered so that the stock is compressed between the shafts. Rewinding then commencesv During rewinding the shafts 22, 24 are rotated by the electric motor 84 to rotate the roller rings 34 at a peripheral speed less than the speed at which the slit stock 6 is drawn through the tensioner by the rewind unit 14. The difference in speeds is adjusted (by means of eddy current clutch 83) such that a tension of more than 80 lbs., e.g., at least about 90 lbs., would be maintained on the stock in the absence of roller rings 34. The effect of roller rings 34 is that as soon as the tension on any given strip exceeds 80 lbs., the roller rings for that strip begin to rotate, to relieve the tension. This reduces the tension back to 80 lbs. for that strip.

It will be noted that rotation of one pair of roller rings 34 will not affect the adjacent roller rings nor tend to cause rotation thereof, because the roller rings are all separated from each other by the friction discs 44 and do not touch each other. I

In this manner, the tension for each individual strip is closely controlled. The tension for any given strip cannot become too low, because if this tends to occur, the roller rings 34 for such strip stop rotating, exerting extra drag on that strip to restore adequate tension to the strip.

If desired, the shafts 22, 24 could be fixed against rotation, allowing all of the slippage to occur between roller rings 34 and friction discs 44. However, this would drastically increase the wear between the roller rings 34 and the friction discs 44. Therefore it is preferred to rotate the shafts 22, 24 (or allow them to rotate), setting the tension at the roller rings slightly lower than that at clutch 83 (since the adjustment at the roller rings allows differences between individual strips). Thus, some rotation occurs at the shafts 82, 84 and some occurs between the roller rings 34 and the friction discs 44.

In the embodiment illustrated, the tension level of the friction plate roller ring assembly is set by turning nuts 70. This can be done conveniently only while the shafts 22, 24 are stopped, since the nuts rotate with the shafts. Under some circumstances it is desirable to be able to adjust the tensionwhile the shafts 22, 24 are rotating. In that event, power means can be used to adjust the tension, as shown in FIG. 6, where primed reference numerals indicate parts corresponding to those of FIGS. 1 to 5. FIG. 6 shows a mechanism for compressing the assembly on shaft 22 (to adjust the tension imparted to strips by the shaft 22 assembly); the arrangement for shaft 24 will be identical. As shown in FIG. 6, the spring disc 66, washer 68 and nut 70 have all been eliminated. Instead, a ring 93 is provided which does not rotate with the shaft 22, but which instead bears against the disc 58 via bearings 92. The ring 93 is supported by the-piston rods 94 of pistons contained in double acting-cylinders 96. The cylinders 96 (which are three or four in number, spaced equally circumferentially around shaft 22) are secured to upright member 18 and are supplied with air or hydraulic fluid to maintain a desired pressure against disc 58. The spring disc 62 at the left hand side of shaft 22 is eliminated. In this manner, the tension on strips being wound can be adjusted as the strips are wound. (In practice, only one cylinder 96 may be used, coaxial with-shaft 24 and mounted on the opposite side of upright 18 from shaft 24, with a plate connected to its piston rod and with rods extending from the plate through upright 18 to bear against ring 93.

Instead of the friction discs, other appropriate means can be employed if desired to control and limit rotation of the roller rings. For example, pneumatic or hydraulic means acting individually on each'roller ring can be employed. The number of roller rings on the unit and their individual widths can be varied as required by the stock being slit.

If desired, the roller rings 34 of one of the shafts, (e.g., shaft 24) can be left free to rotate, (i.e., its friction discs 44 and end discs would not be keyed to the shaft), so that rotation is controlled only for the roller rings 34 of the other shaft, (e.g., shaft 22). A somewhat I similar result would be accomplished by not connecting shaft 24 to the clutch 83 and motor 84. However, better tension control is achieved when the rotation of the roller rings on both shafts is controlled. The invention may be used for metal, plastic, paper, textiles, wire, or any other stock where multiple strips or strands are being wound simultaneously. The term strip as used in this description and in the appended claims is intended to include strands, e.g., of wire.

I claim:

1. A tensioner for tensioning a plurality of parallel side by side strips, comprising:

1. a pair of parallel spaced shafts,

2. a plurality of roller rings rotatably mounted on each shaft, one ring on each shaft for each strip to be tensioned, said rings each having outer circumferential friction facings, said shafts being spaced to support said roller rings of one shaft adjacent and opposed to the facings of corresponding rings of the other shaft, for said strips to pass therebetween,

3. friction means connected between each said shaft 1 and said roller rings thereof for controllably limiting rotation of said roller rings of each shaft relative to such shaft, said friction means comprising friction discs keyed to each said shaft for axial movement thereon, one friction disc being located between each adjacent pair of roller rings and said friction discs being of lesser diameter than said roller rings, said friction discs spacing said roller rings of each shaft axially apart to provide axial spaces of predetermined width between the outer portions of said roller rings of each of said shafts,

4. a plurality of annular separator discs each of axial thickness less than said predetermined width, said separator discs having central apertures of diameter greater than that of said friction discs and less that that of said roller rings, said separator discs being mounted over said friction discs of one of said shafts between said roller rings thereof and being freely rotatable on such friction discs, said separator discs being slidable axially on said friction discs on which they are mounted but such axial movement of said separator discs being limited by the sides of such roller rings, said separator discs being of outer diameter greater than that of said roller rings and projecting into said spaces between the outer portions of said roller rings of the other of said shafts, to prevent sideways movement of said strips relative to said roller rings while reducing drag on the edges of said strips,

5. means for controllably compressing said roller rings and friction discs of each shaft axially to limit rotation of said roller rings of each shaft,

6. and common means for limiting rotation of each shaft.

2. Apparatus according to claim 1 wherein the spacing between said first and second shafts is adjustable, to admit strips of different thicknesses.

3. Apparatus according to claim 2 wherein said 'means for limiting rotation of said shafts comprises means connected to said shafts for rotating said'shafts to rotate said roller rings at a peripheral speed less than the speed at which said strips are to be drawn through said tensioner. i

4. Apparatus according to claim 2 wherein said means for controllably compressing said roller rings and said friction discs includes a stop member at one end of said roller ringsfor limiting movement of said roller rings in one direction, pressure means at the other end of said roller rings for compressing said roller rings against said stop member, and power operated means for applying pressure to said pressure means to compress said roller rings against said stop ring during rotation of said shafts. 

1. A tensioner for tensioning a plurality of parallel side by side strips, comprising:
 1. a pair of parallel spaced shafts,
 2. a plurality of roller rings rotatably mounted on each shaft, one ring on each shaft for each strip to be tensioned, said rings each having outer circumferential friction facings, said shafts being spaced to support said roller rings of one shaft adjacent and opposed to the facings of corresponding rings of the other shaft, for said strips to pass therebetween,
 3. friction means connected between each said shaft and said roller rings thereof for controllably limiting rotation of said roller rings of each shaft relative to such shaft, said friction means comprising friction discs keyed to each said shaft for axial movement thereon, one friction disc being located between each adjacent pair of roller rings and said friction discs being of lesser diameter than said roller rings, said friction discs spacing said roller rings of each shaft axially apart to provide axial spaces of predetermined width between the outer portions of said roller rings of each of said shafts,
 4. a plurality of annular separator discs each of axial thickness less than said predetermined width, said separator discs having central apertures of diameter greater than that of said friction discs and less that that of said roller rings, said separator discs being mounted over said friction discs of one of said shafts between said roller rings thereof and being freely rotatable on such friction discs, said separator discs being slidable axially on said friction discs on which they are mounted but such axial movement of said separator discs being limited by the sides of such roller rings, said separator discs being of outer diameter greater than that of said roller rings and projecting into said spaces between the outer portions of said roller rings of the other of said shafts, to prevent sideways movement of said strips relative to said roller rings while reducing drag on the edges of said strips,
 5. means for controllably compressing said roller rings and friction discs of each shaft axially to limit rotation of said roller rings of each shaft,
 6. and common means for limiting rotation of each shaft.
 2. a plurality of roller rings rotatably mounted on each shaft, one ring on each shaft for each strip to be tensioned, said rings each having outer circumferential friction facings, said shafts being spaced to support said roller rings of one shaft adjacent and opposed to the facings of corresponding rings of the other shaft, for said strips to pass therebetween,
 2. Apparatus according to claim 1 wherein the spacing between said first and second shafts is adjustable, to admit strips of different thicknesses.
 3. Apparatus according to claim 2 wherein said means for limiting rotation of said shafts comprises means connected to said shafts for rotating said shafts to rotate said roller rings at a peripheral speed less than the speed at which said strips are to be drawn through said tensioner.
 3. friction means connected between each said shaft and said roller rings thereof for controllably limiting rotation of said roller rings of each shaft relative to such shaft, said friction means comprising friction discs keyed to each said shaft for axial movement thereon, one friction disc being located between each adjacent pair of roller rings and said friction discs being of lesser diameter than said roller rings, said friction discs spacing said roller rings of each shaft axially apart to provide axial spaces of predetermined width between the outer portions of said roller rings of each of said shafts,
 4. Apparatus according to claim 2 wherein said means for controllably compressing said roller rings and said friction discs includes a stop member at one end of said roller rings for limiting movement of said roller rings in one direction, pressure means at the other end of said roller rings for compressing said roller rings against said stop member, and power operated means for applying pressure to said pressure means to compress said roller rings against said stop ring during rotation of said shafts.
 4. a plurality of annular separator discs each of axial thickness less than said predetermined width, said separator discs having central apertures of diameter greater than that of said friction discs and less that that of said roller rings, said separator discs being mounted over said friction discs of one of said shafts between said roller rings thereof and being freely rotatable on such friction discs, said separator discs being slidable axially on said friction discs on which they are mounted but such axial movement of said separator discs being limited by the sides of such roller rings, said separator discs being of outer diameter greater than that of said roller rings and projecting into said spaces between the outer portions of said roller rings of the other of said shafts, to prevent sideways movement of said strips relative to said roller rings while reducing drag on the edges of said strips,
 5. means for controllably compressing said roller rings and friction discs of each shaft axially to limit rotation of said roller rings of each shaft,
 6. and common means for limiting rotation of each shaft. 